Hurricane Helene is now forecast to make landfall along Florida's Gulf Coast on Thursday evening at Category 4 strength, the National Hurricane Center said on Wednesday evening.

The storm is expected to bring "catastrophic and deadly storm surge" to a large portion of Florida and the Southeast, meteorologists warned. The storm surge could reach as high as 20 feet.

The governors of Florida, Georgia, South Carolina and North Carolina declared states of emergency ahead of Helene's arrival. The Tampa International Airport announced that it will suspend operations on Thursday.

Multiple counties in Florida issued mandatory evacuation orders for people in low-lying areas. Residents in the storm's potential path have been told to prepare for up to a week without electricity.

"It's a big, big storm," Florida Gov. Ron DeSantis said at a press briefing Wednesday. "Many people will lose power ... be prepared for that."

Where is the storm and what is its path?

According to the NHC's 5 p.m. ET advisory, Helene — with maximum sustained winds of 85 mph — was located about 460 miles southwest of Tampa, Fla., and was moving north at 12 mph.

The storm is expected to rapidly intensify and come ashore in Florida's Big Bend region with winds of 130 mph, forecasters said.

In addition to high winds, the storm will threaten millions of residents along the Gulf Coast with heavy rainfall, as well as the possibility of tornadoes. Before it heads up into the Gulf of Mexico, Helene will bring heavy rain to portions of the western Caribbean, potentially mudslides and flooding across western Cuba. The system will also pose the threat of inland flooding across several U.S. states.

"Considerable flash and urban flooding is expected across portions of Florida, the Southeast, southern Appalachians, and the Tennessee Valley Wednesday through Friday," the National Hurricane Center said.

There is the potential for life-threatening storm surge along the entire Florida peninsula, the weather service warned.

A peak storm surge of up to 20 feet is possible along portions of Florida's Gulf Coast.

How is Florida preparing?

DeSantis expanded a state of emergency on Tuesday to 61 counties ahead of the storm. Helene is expected to make landfall near the Big Bend region of the Florida panhandle, which was pummeled by Hurricane Debby earlier this season.

The declaration allows the state to execute its Comprehensive Emergency Management plan, allowing the use of resources for any logistical, rescue or evacuation operations.

“Now is the time to make an emergency plan, know your evacuation zone, and be as prepared as possible for the storm,” DeSantis said in a post on X.

Many cities and counties in Florida opened designated sites for residents to fill sandbags ahead of the storm.

Evacuation zones

Officials urged people in low-lying areas to consult a website outlining evacuation zones, and to heed evacuation orders. Mandatory evacuations were issued in 14 counties, including Pinellas and Hillsborough, as of midday Wednesday.

The University of Tampa, which is in one of the zones under mandatory evacuation orders in Hillsborough County, said it was working evacuate all residential buildings on its campus.

The Tampa Bay Bay Times reported that many grocery stores in the Tampa area sold out of water Tuesday as hurricane shoppers stocked up on supplies.

Watches and warnings

As of 5 p.m. ET on Wednesday, a hurricane warning was in effect for:

Anclote River to Mexico Beach, Florida

Cabo Catoche to Tulum, Mexico

A "hurricane warning" means that hurricane conditions are expected somewhere within the warning area. It is typically issued 36 hours before the anticipated arrival of tropical-storm-force winds.

A hurricane watch was in effect for:

Pinar del Río Province, Cuba

Englewood to Anclote River, including Tampa Bay

A "hurricane watch" means hurricane conditions are possible within the watch areas. It is usually issued 48 hours before the hurricane is anticipated to hit.

A tropical storm warning was in effect for:

Dry Tortugas

All of the Florida Keys

The west coast of Florida from Flamingo to Anclote River, including Tampa Bay

West of Mexico Beach to the Okaloosa/Walton County Line

Lake Okeechobee

Rio Lagartos to Tulum, Mexico

Cuban provinces of Artemisa, Pinar del Rio, and the Isle of Youth

A "tropical storm warning" means that tropical storm conditions are expected in the warning areas within the next 36 hours.

A storm surge watch was in effect for:

West of Indian Pass to Mexico Beach

A "storm surge watch" indicates the possibility of life-threatening flooding, such as rising water moving inland from the coast.